The LEGO MINDSTORMS NXT Zoo!: A Kid-Friendly Guide to Building Animals with the NXT Robotics System by Fay Rhodes. The companion web site to the book, "LEGO MINDSTORMS NXT ZOO!" features the following:
Illustrations of all nine models in the book
A tutorial on parts substitutions for the models in the book
Downloadable instructions for producing animal sounds for your NXT (for both Windows and Mac)
Little-known facts about the real animals that the models represent
A complete parts list for every model in the book
Links to where you can buy every part used in the book (via Bricklink)
Lists of other LEGO models that use the same parts as those in the book (via Peeron)
The Tech Museum of Innovation's Robot Zoo
Tufts University Animal Robots
Make sure and click on the animal gallery and the animal movie!
NXT Animal Videos
NXT Animal Ideas
Related Science NetLinks Resources